<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    body {
      height: 100vh;
    }

    @media screen and (max-width:600px) {
      body {
        background: red;
      }
    }

    @media screen and (min-width:600px) and (max-width:1000px) {
      body {
        background: yellow;
      }
    }

    @media screen and (min-width:1000px) {
      body {
        background: green;
      }
    }
  </style>
</head>

<body>
  <div class="content"></div>
</body>

</html>